(C) 2000 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint. Printed in Malaysia. Discrete Dynamics in Nature and Society, Vol. 5, pp. 203-221 Reprints available directly from the publisher Photocopying permitted by license only Bifurcation Analysis of the Henon Map ZHANYBAI T. ZHUSUBALIYEV ’*, VADIM N. RUDAKOV a, EVGENIY A. SOUKHOTERIN and ERIK MOSEKILDE b aKursk State Technical University, Department of Computer Science, 50 Years of October Street, 94, 305040 Kursk, Russia," b Center for Chaos and Turbulence Studies, Department of Physics, Technical University of Denmark, 2800 Lyngby, Denmark (Received 15 March 2000) Division of the parameter plane for the two-dimensional H6non mapping into domains of periodic and chaotic oscillations is studied numerically and analytically. Regularities in the occurrence of different motions and transitions are analyzed. It is shown that there are domains in the plane of parameters, where non-uniqueness of motions exists. This may lead to abrupt changes of the character of the dynamics under variation in the parameters, that is, to a sudden transition from one stable cycle to another or to chaotization of the oscillations. Keywords: H6non two-dimensional mapping; Chaos; Bifurcations; Branching pattern Here a is the nonlinearity coefficient and/3 is the coefficient of dissipation ([/31 < 1). T denotes the operation of transposition. The mapping (1) was originally proposed by H6non (Hdnon, 1976) as a model of the Poincar6 map for a three-dimensional flow system. Since 1. INTRODUCTION The purpose of this paper is to apply bifurcation analysis and continuation methods to study regularities in the occurrence of different motions in the two-dimensional H6non map (H6non, 1976; Hitzl and Zele, 1981): then it has been extensively studied both numerically and from a more theoretical point of view (for references see, e.g., Schuster, 1984; Berg6 et al., 1984; Moon, 1987; Anishchenko, 1990; Landa, 1996). Curry (Curry, 1979) was the first to observe that there exists a range of parameters for which two chaotic attractors coexist, and Derrida et al. (Derrida et al., 1979) showed how the Xk--F(Xk-1); k--l,2,...; X- (xl, x2) r" F- (fl,f2) r" fl OZX -+- X2; *Corresponding author. 203 204 Z.T. ZHUSUBALIYEV et al. period-doubling cascade in the H6non map for certain parameter values follows the Feigenbaum scenario. At the same time, Newhouse (Newhouse, 1974) found that there are regions in parameter space in which a dense set of the stable periodic orbits with extremely small basins of attraction may exist. For a more recent discussion of this phenomenon see, e.g., Kan et al. (Kan et al., 1995). A variety of different motions generated by the two-dimensional H6non map (Simo, 1979; Hansen and Cvitanovi6, 1998) in dependence of the parameters and peculiarities in the occurrence of chaos are typical of a wide class of dynamical systems (Schuster, 1984; Moon, 1987; Anishchenko, 1990; Mosekilde, 1996). As shown, for instance, by Anishchenko (Anishchenko, 1990) the map (1) is a good representation of a three-dimensional model of a radiophysical generator with inertial nonlinearity. In particular, it is shown that the collection of bifurcations in the plane of the controlling parameters c and/3 is qualitatively equivalent to that which is realized in the Poincar6 map of a model of the generator. We have found a similar equivalence when analyzing models of a specific class of automatic control systems, for example, two- and three-dimensional models of systems with pulse-width modulation and a four-dimensional model of a relay system with hysteresis (Baushev and Zhusubaliyev, 1992; Baushev et al., 1996; Zhusubaliyev, 1997; Zhusubaliyev, 1997a). Many other non-linear dynamical systems display a structure of division of the parameter plane and a shape and arrangement of the domains of stability similar to what we shall discuss here. The peculiarities of organization of domains of stability with the specific shape, referred to as a swallow tail, or a crossroad area and denoted here as walw can be observed with bimodal one-dimensional maps as shown in (Gallas, 1994), for the Ikeda map (Mosekilde, 1996), and for several other nonlinear dynamical systems (Barfred et al., 1996). Detailed analysis of such a structure have been performed by Kuznetsov et al. (Kuznetsov et al., 1993) and, from a more mathematical point of view, by Mira et al. (Mira et al., 1996) (see also II references in this work). It is shown in (Kuznetsov et al., 1994), that a quantitative universality in the transition to chaos in two-dimensional H6non-like maps exists. Hansen and Cvitanovi6 (Hansen and Cvitanovi6, 1998) describe the possible bifurcation structures for maps of the H6non type, in particular some swallow tail for various periods using a series of n-unimodal approximations and the associated symbolic dynamics. Sonis (Sonis, 1996) provides a detailed description of the bifurcation phenomena in the H6non map. Nonetheless, the complete bifurcation scenario for the H6non map has not yet been established, and the aim of the present article is to present a number of results that appear not to have been given in the above works. Special emphasis is paid to the study of the structure and properties of the division of the plane of controlling parameters for the dynamical system (1) into the domains of existence of periodic motions and chaos. 2. DIVISION OF PARAMETER PLANE Let us begin with some preliminary notes. Let Xci, i= 1,m be a periodic motion (m-cycle) of the dynamic system (1). It is evident that all Xc;, i-- 1, m satisfy the following equation Xc Fm(Xc) O, Fm(Xc) F(F(... (F(Xc)) ...)) times (2) The local stability of the m-cycle is determined by the eigenvalues (multiplicators) pl and p2 of the These are the roots of the basic matrix equation m. det(m pE) OF(Xc(i-1)) i-l, GO OXc( iOF(Xc(i-1)) OXc( i- O, 1,m E,i -2OXlc(i-1) o BIFURCATIONS OF THE Here E is the unit matrix. Let II {(c,/3): # < c < u; </3 < } be the set of the parameters of the dynamic system (1). A point in the plane P (c,/3) EII corresponds to every fixed set of parameter values. Let X.i(P), 1,m be a locally stable m-cycle corresponding to point P. Let IIk,j- be the simply connected set of parameters I-[k, j C I-I, k 1; j 1,2,..., s such, that for every P E IIk,j there exists a stable m-cycle X,i(P), 1, m, which is continuous along the parameters in IIk,.. If there are several motions at fixed P, different IIk,v. correspond to different motions. The k-cycle for Ilkd is minimum, that is, there is no mcycles with m < k in llk,.. The index j is introduced to distinguish sets, having the same k. The value of HI’NON MAP denote these curves as N+ and N_, respectively. For the dissipative system (1), the case where two complex conjugate eigenvalues cross the unit circle cannot occur. It is interesting to study the possibility of nonempty intersections of the sets Yik,j and the properties of IIk,v. in whole in order to understand the great variety of different motions, generated by the dynamical system (1). In the following we shall restrain ourselves to the region II={(c,/3): -1<c<4; 1/31<1}. Let us first consider the solutions of Eq. (2) and study the local stability of m-cycles. has the form: Equation (2) when m + s may be finite or infinite. X2 The boundaries of the sets following types: IIk,.. may be of the simple, that is, there is a stable m-cycle for any points P 1-’k,v-, connected with a limitation of the parameter variation range; the boundaries Pk,. are formed by the collection of bifurcation values of parameters or by the collection of points of accumulation, corresponding to aperiodic motions. The point P, II is a bifurcation point, if the equation (Neymark and Landa, 1987; Butenin et al., 1987) x(P, P) x(P, p) [92 --]- 205 lP @ 2 det(m 0; Xlc" - The roots of this equation determine two period- cycles X X2c /Xlc. The domain of existence of a stable 1-cycle is limited by bifurcation curves N+, N_ /32-2/+4c+1 =0 (4) and 3/2 6/3 O, 4c + 3 O, pE) respectively. Let us denote this domain as 1-I1,1 has a root, which is on the unit circle, when P- P.. These are the cases, when the greatest multiplicator of m-cycle (in absolute value) turns into or -1. The corresponding bifurcation curves are determined by the equations x(P, 1) x(P,-1) +1 @2 1 @2 0 0 By analogy with (Neymark and Landa, 1987; Butenin et al., 1987) here and in the following we II1, II1 { (OZ,/) 1) 2, I/l < }, then Eq. (3) has If the parameters P <c< (1/4)(/3 no real roots. On the curve c -1 </3 < Eq. (3) takes the form =0 (1/4)(/3- 1)2, Z.T. ZHUSUBALIYEV 206 and has a multiple root. When changing the parameters along some smooth curve (referred to as the trajectory of deformation) into the domain a>-(1/4)(/3-1)2, -1</3<1, two solutions arise: one of which corresponds to a stable 1-cycle and the other to an unstable 1-cycle. This pair of 1-cycles occurs abruptly in a saddle-node bifurcation at a--(1/4)(3-1) 2. In a reverse transition, the stable 1-cycle disappears as it coincides with the unstable cycle at the points of intersection with the trajectory of deformation and curve (4). It is easy to see, that a- (1/4)(/3- 1)2 < 0. Now let us follow the evolution of the stable and unstable 1-cycles with variation in a from negative values to positive ones by passing through a-0. Denote the solutions of the Eq. (2) as X XUc, that correspond to stable 1-cycle and unstable 13=0.2 o ot (a) s, -cycle. When a et al. PlP2 [3=0.2 P; 0, Eq. (2) has only one solution Xlc It is obvious, that ’ X2c 3 0.3 -0. t6 lim -,+/-o s x 1-/3’ lim -++o xzSc Hence the solution of Eq. (2), which corresponds to the stable 1-cycle, depends smoothly on the parameters in IIl,1, whereas XU is uninterrupted in 1-[1,1 except for the points, in which a- 0. In points a-0, 1/31 <1 the solution XcU has an infinite discontinuity. The distinction in the nature of the parameter dependence of the solutions Xcs and XcU is shown in Figure l(a). The dependences of the multiplicators of stable and unstable 1-cycles are given in Figure (b). When the trajectory of deformation and the bifurcation curve (5) intersect, the 1-cycle loses its stability, and a stable 2-cycle arises softly as the result of a period-doubling bifurcation. Both 1cycles continue to exist as unstable over the whole range of parameters beyond bifurcation curve (5). FIGURE (a) Variation of the stable and unstable period-1 cycles with the nonlinearity parameter c. Note the different nature of these dependences. (b) Corresponding variation of the multiplicators Pl and/)2. Equation (2) when m- 2 takes the form oz3X41c 2o2Xc q- (1 fl)3Xlc- (1 -/)2 @ o X2c 1- 0; This equation has four real roots in the domain a > (3/4)(/3- 1) 2. Two of the roots correspond to two unstable 1-cycles. It is not difficult to show, that a stable 2-cycle satisfies the equation O2Xc X2c c(1 -/3)Xlc + (1 -/)2 (1 aX21c)" -/3 o 0; (6) BIFURCATIONS OF THE 6/3 4c 5 (7) 0 that is, H2,- (oz,/3)’(/3-1 _<oz <1 5), I/ 1 < (5/32 6/3 o6Xtc o5(1 t)Xc oz4((1 )2 3oz)Xlc_ nL }. o(1 )(1 -t-/32 2oz)Xc+ qL_ 2 (4 2 @ (3 @ 2. ). + ty When passing through the boundary (7) into the domain of values c > (1/4)(5/32- 6/3-5), 1/31 < 1, a stable 4-cycle arises softly, and the 2-cycle continues to exist, but becomes a saddle. It becomes more and more difficult to obtain bifurcation formulas in explicit form for m- 2;-1, i- 3, 4,... All the rest of the sets H2/-l,1, i-- 3, 4,... were built numerically. The collection of H2,-l,1, i-- 1,2,... which forms 1-I1,1, is shown in Figure 2: (1 2+2 4fl5fl2 4fls + 4_ 2fl2) 0. The roots of this equation can be found only numerically. Let us try to find the equation of bifurcation curve N+ for the 3-cycle. Taking into account, that with parameter values, located on the curve N+, Eq. (8) has only multiple roots, we U fi>’,, n,,, 207 In this way, the set II1,1 consists of domains of existence of stable 2i-l-cycles (i-1,2, 3,...). The boundaries, separating these domains in correspond to period-doubling bifurcation curves. The set I-[1,1 is limited by bifurcation curve (4) from the left and by a curve formed by the collection of accumulation points from the right. Now consider I-[k, j --Uie=l l-Ik.2i-l,j for k-/= 1. From Eq. (2) when m- 3 we find The set H2,1, whereupon a stable 2-cycle is determined, is limited by the bifurcation curve (5) and by the curve, defined by the following equation 5/2 HI’NON MAP i=1 -1 -1 FIGURE 2 The collection of the sets I]2,-,,1, diverge to infinity with any initial conditions. et 4 1,2,... which forms 1-I,1, I] and I denote those domains of H, where trajectories Z.T. ZHUSUBALIYEV et al. 208 obtain 2c /Xc + x + which were obtained numerically. Naturally, Figure 4 represents only those sets, that are relatively large in II. The resulting picture for the division of Hdnon o. Here 2 -/3-/3 +/3 2/ (2c c qt_ /4 qt_/5 nt O2/_ 2Ct/33) o- where 0 +/3 -+-/2 q__/4 q_ 5 q_/6 c( 2c q- O 2 4/3 5/2 4 +/4 2cfl2). Then the desired bifurcation curve will lie on the two-dimensional surface (Fig. 3(a)) mapping parameter plane II {(c,/3): < c < 4; 1/31 < into domains of various oscillatory modes, is shown in Figure 5. The domains of chaoticity adjoin to the parts of boundaries of 1-I,., formed by the set of accumulation points. The diagram depicts only one of them, which occupies the largest region in the parameter plane. The domain is shown in Figures 4, 5 by dark hatching and is denoted as l-[Chao s. The remaining domains are very narrow and hence, are not shown in the diagram. There is a great number of windows with deterministic dynamics within IlChaos, which begin with saddle-node branching m-cycles. The inner structure of such domains may be similar to that for Ilk,./or be different. The domains, whose properties are different from the properties of fik,.j, are denoted as Hswallw (see Fig. 4). The structure of and the bifurcations in this domain were described in some detail in (Dmitriev et al., Ilfwallow We find an equation for the bifurcation curve, by setting X(c,/3, 1) equal to zero: --8[#(Ct,/)](1/2) _+_ (1 )(1 +/)2 0. The form of this curve is shown in Figure 3(b). The remaining domains II3.2i-,1 i-2,3,..., as well as ]-[2/-,1, i--3, 4,..., were built numerically. Figure 4 shows the collection 1-[3,1 U3.2 i-1,1 U fik’2i-I l-[k,1 i=1 k i=1 5, 6, 7, 8, 10, 12 1994). For any point P C Il with the exception of P=(0,0) there is such (simply or not simply connected) domain D, in the phase space of the dynamic system (1), that if X0 c D,, then lim X(X0)]]- oc, X(Xo) F(Xo). In Figure 5 (cf. also Fig. 2) lii and M 2 denote those domains of II (not hatched), where Eq. (9) with any X0 is valid for all points P I)l t I)2. As seen in Figures 4, 5, all sets FI,.j, with the exception of wallw, have non-empty intersections with II,. Moreover 11i,l Ilq,p (i, q 1, i- q). This means, that there exist different stable m-cycles, corresponding to IIi, and IIq,p for every II P IIi, lf’qilq, p. It is easy to see, that and IIk,2 U 1-Ik’2i-’, i=1 2’ k 5, 6, 8 (9) II3,1 Cl AI-I II5swallw wallw 5, b, 1-IiSwallw i7 j. BIFURCATIONS OF THE FIGURE 3 (a) The 2D surface, on which the bifurcational curve 3-cycle. Based on these results let us elaborate on the bifurcations analysis, while moving along the parameters in the domain (U(,.j)H,..) u fIChao in more detail. The analysis was made in the sections /3=0.3; /3=0.68 and /3=0.5, changing the parameter c over the range of - ..-a(- 1) 2 < c < u, 1/31 < 1, u < 4, (u, const)}. The bifurcation diagrams calculated for these values of / and the indicated variation of c are N+ HI’NON MAP 209 for 3-cycle lies. (b) The curve of saddle-node bifurcation for depicted in Figures 6(a), 7(a) and 8. It is easy to see in these diagrams, that the complication of oscillations happens through a sequence of period-doubling bifurcations while continuously increasing c. These sequences lead to the appearance of aperiodic motion with some critical value of cx and then to the domain of chaoticity. The ranges of variation in c in which chaotic oscillations are observed, are interrupted by small intervals, where stable cycles exist (Figs. 6-8). In the domain -(1/4)(fi/- 1) 2 < Oz < 1/1 < 1, , < 4, (t,,/3 const) with variation in c many other stable motions occur in saddle-node bifurcations, such as 3-, 6-, 8-, 18-cycles and other motions with , Z.T. ZHUSUBALIYEV 210 et al. H/0,1 H6,1 -1 -1 FIGURE 4 The collections of the sets ]-I3,1, Ik,2i-,,l,i the chaoticity. ot 1,2,... ,k 4 5, 6, 7,8, 10, 12 and I-[k, 2, k- 5, 6,8. Here IIChao is the domain -1 FIGURE 5 Resulting picture for the division of H6non map parameter plane into domains of various oscillatory modes. subsequent period-doubling bifurcations. That is why the general pattern of cycles branching is complicated significantly. Let us follow the evolution of various stable cycles, with variation in c. The results of numerical calculations for /3=0.3 and /3=0.68 are presented in Tables I, II. In these tables the second column contains the periodicity of a cycle, the forth and the fifth columns are the range of c, in which locally stable m-cycle exists. The last column indicates the width of this range. It is convenient to represent the data of the tables in the form of a diagram, which was called branching pattern (Figs. 6(b) and 7(b)) in BIFURCATIONS OF THE HI’NON MAP 211 2.5 13=o.3 -1.5 13=0.68 -2.5 0.0 ot 0.65 1.4 (a) 0.98 ot (a) 40 50 13=0.3 m 2 1.4 0 (b) FIGURE 6 (a) Bifurcation diagram and (b) branching pattern for 0 _< c _< 1.4 and/3 =0.68 0.3. (g) FIGURE 7 (a) Bifurcation diagram and (b) branching pattern for 0.65 _< c < 0.98 and/3-0.68. 2.5 (Baushev and Zhusubaliyev, 1992; Baushev et al., 1996). In these diagrams values of varying parameters are plotted on the horizontal axis and values of m are plotted on the vertical axis. Further, we use designations as in (Baushev et al., 1996). Vk,j. are the branches, where index k indicates from which k-cycle the branch begins. The maximum value j indicates the number of observed branches, having the same k. All branches start with k-cycles, which arise in a saddle-node bifurcations. Some Vk,j are determined on sets, that were not shown in Figure 5, as their sizes in parameter plane are too small. Xi -2.5 0.7 1.074 ot FIGURE 8 Bifurcation diagram for 0.7 < /3=0.5. c _< 1.074 and Z.T. ZHUSUBALIYEV et al. 212 TABLE Vk,j O i-1 m Vl,1 V6, V7, V20,1 V2,1 2 4 8 16 32 64 6 12 7 14 28 56 20 21 OZ 2.k, 2 3 4 5 6 7 2 2 3 4 --0.1225 0.3675 0.9125 1.0258554050738 1.0511256620352 1.0565637581588 1.0577304656609 1.062372 1.0710703629071 1.2266174 1.2541834642429 1.2600151726701 1.2614289068416 1.067564 1.26887 2.k, 0.3675 0.9125 1.0258554050738 1.0511256620352 1.0565637581588 1.0577304656609 1.057956 1.0710703629071 1.0750124047736 1.2541834642429 1.2600151726701 1.2614289068416 1.2617 1.0677430954543 1.2692033433938 / 0.49 0.545 0.1133554050738 0.0252702569614 0.0054380961236 0.0011667075021 0.0002255343391 0.0086983629071 0.0039420418665 0.0275660642429 0.0058317084272 0.0014137341715 0.0002710931584 0.0001790954543 0.0003333433938 TABLE II i- O2.k, V1, V6,2 Vs, V18,1 2 4 8 16 32 64 6 12 24 48 8 16 32 64 18 36 2 3 4 5 6 7 2 3 4 2 3 4 2 0.0768 0.808 0.9169381427467 0.9361479503607 0.9400330556502 0.9408680756308 0.70142261 0.7343659105724 0.7445017603884 0.7467731395103 0.70791248 0.713479366256 0.7158180118385 0.7163564950326 0.74696954 0.7476245768696 The range of existence of each branch Vk,.. is presented in the form of intervals Here the parameters OZ2ik,j, i= 1,2,... correspond to loss of stability of the 2 i- k-cycle and soft occurrence of the 2ik-cycle. When increases, the intervals /OZZik, j O2i+lk, j --OZZik, j Of the existence of the 2ik-cycle become narrower (see Tabs. I, II), so that each branch has its limit value of ck,j*, which corresponds to aperiodic motion. We shall call these parameters accumulation points as ozi2.k, 0.808 0.9169381427467 0.9361479503607 0.9400330556502 0.9408680756308 0.9410471449543 0.7343659105724 0.7445017603884 0.7467731395103 0.7472652867434 0.713479366256 0.7158180118385 0.7163564950326 0.7164739420036 0.7476245768696 0.7479207404767 / 0.7312 0.1089381427467 0.019209807614 0.0038851052895 0.0008350199806 0.0001790693235 0.0329433005724 0.010135849816 0.0022713791219 0.0004921472331 0.005566886256 0.0023386455825 0.0005384831941 0.000117446971 0.0006550368696 0.0002961636071 in (Baushev et al., 1996). The accumulation points are shown in Figures 6(b) and 7(b) as vertical lines. The beginning of the windows of periodicity in the bifurcation diagrams coincides with the beginning of the branches. Some of Vk,(k: 1) intersect with V1,1. In those ranges of c, where V, [..J Vk,.-Cb, k-/: 1, there exist both a stable 2 i- 1-cycle and stable 2 d- k-cycle, k _> 3; i, d_> 1. This means, that the phase plane (x,x2) of the dynamic system (1) comprises some basins of attraction of different cycles. In this case the 2 i- 1-cycle or the 2 d- kcycle are chosen, depending on the initial BIFURCATIONS OF THE conditions. The character of division of the iphase plane of system (1) into basins of attraction of different cycles is shown in Figures 9-11. Figures 9(a) and (b) display basins of attraction for the 1-cycle and the 3-cycle (P=(0.949;-0.744)). HI’NON MAP 213 In Figure 10 we show basins of attraction for the 1-cycle, the 18-cycle, and the 3-cycle, (P=(1.0295;-0.8)), and in Figure 11 are basins of attraction for the 2-cycle and the 8-cycle (*’ (0.53;0.SS)). X -0,7 x, (a) FIGURE 9 (a), (b) Basins of attraction for the 1-cycle and the 3-cycle with 1,6 c 0.949, fl -0.744. (See Color Plate II.) Z.T. ZHUSUBALIYEV 214 -2 et al. FIGURE 10 Basins of attraction for the 1-cycle, the 18-cycle, and the 3-cycle with FIGURE Basins of attraction for the 2-cycle and the 8-cycle with c The location of X,k, k-- 1,m, are marked by dots in Figures 9-11. The non-hatched parts of Figures 9 and 10 correspond to the collection of initial conditions from which the trajectories diverge to infinity (see(9)). One can see from the comparison of the branching pattern with the bifurcation diagrams 2 X (-- 1.0295,/3= -0.8. (See Color Plate III.) 0.53, /3= 0.88. (See Color Plate IV.) that there are intervals within the limits of existence of the V,I where periodic motions coexist with chaotic oscillations. Here, the system may chose a periodic motion or chaotic oscillations, depending on the initial conditions. As an example Figure 12 gives the result of plotting of the basins of attraction for the FIGURE 12 Basins of attraction for the coexisting 6-cycle and chaotic motion with s =1 .7, fl = -0.03 . (See Color Plate V .) a (a) + 1' 0,5 Swallow A 5,1 Swallow 10,1 Fold ) 1,5 I ^ Swallow I10,2 (U) FIGURE 13 (a) The 2D surface illustrating the peculiarities of organization of the domains of existence for 5-cycle Itiallow and 10cycle ~SO,ill°" and Ilso211ow which are of a "swallow tail" kind . (b) Bifurcation curves bounding the domains H a11 o`" fl Mow and nsozlloW Note that both plots are not drawn to scale . 216 Z.T. ZHUSUBALIYEV coexisting 6-cycle and chaotic motion (P= (1.7;-0.03)). Now let us consider the difference between the properties of the set wSwaow and the set 11,... Similarly to (Anishchenko, 1990), when analyzing the model of the radiophysical generator with inertial non-linearity, we introduce and consider a three-dimensional space (,/3, x.(P)), in which we depict the dependence x,:(P). Here, as in (Anishchenko, 1990), by x..(P) we mean one of component of the fixed point X:(P) of the mapping X:=F’(X:). The locus, corresponding to stable and unstable m-cycles, forms a twodimensional surface 6)m,.i in (c, ,x:(P)). The first index in the designation of (3m,.. indicates the value of m, for which the surface was built, and the second index is introduced to distinguish (R),.., having the same m. The plot of such a surface for m= 5 and m= 10 is schematically shown (6)5,1 and 6)10,1, 6)10,2) in Figure 13(a). Now we shall project an image of the surface 6),.. onto the plane of control parameters (Fig. 13(b)). For the purpose of illustration, the et al. bifurcation curves in Figure 13 are not drawn to scale. The domains of existence of the stable 5cycle and the stable 10-cycles are denoted as Swallow Swallow Swallow 115,1 and H10,1 ,1110,2 respectively. The set Swallow 1-[5,1 is limited_by the period-doubling bifur_c_tion curvves P,5 P 1,5 and the curves P+0,5’ P+1,5’ 1,5 (P,5, Pl,5 -are the lines of fold (Arnold, 1990) of to combination of the stable 5-cycle and the + 5-cycle (the curve N+ ). The curves P+1,5 and 1,5 are supported by the (35,1), corresponding unstable Swallow Fold of codibifurcation point O Fld 1-I5,1 1,5 (01,5 mension 2 (the point of assembly (Arnold, 1990) of Swallow the projection 5,1), forming a sector in 115,1 where two stable 5-cycles and two unstable 5cycles exist. One of the unstable 5-cycles occurs together with the stable 5-cycle on the boundary p+0,5" The picture below the curves P{5 and Swallo (Figs. 13, repeats structure described for 115,1 and 14). The bifurcation curves j- 1,...,2 i-1", i- 1,2,... accumulate, and there FIGURE 14 The results of numerical calculations of the domains nSwllow k P75-2’---’ 5, 6, 7 8 and some others. (See Color Plate VI.) BIFURCATIONS OF THE HINON MAP 217 cz=1.53 o.14 O. 165 f (a) 50 Vs2 ct=1.53 m o.4 f3 FIGURE 15 (a) Bifurcation diagram for c=1.53 and 0.14_</3<0.165 and (b) branching pattern for c=1.53 and 0.145 _</3 _< 0.162. This section intersects that region of the domain 1-I5Swallw where two stable 5-cycle coexists. exist transversal directions along which infinite series of period-doubling bifurcations take place. , The projections of the two-dimensional surfaces i= 2, 3,...) lm,j, (m 5 2 i- j= 1,..., 2 ionto the place of control parameters have the same peculiarities as 5, (Fig. 14). The domain II5swallw consists of the collection of the sets ; Swallow 1-[5.2i_1,j j- 1,..., 2 i- 1., i- 1,2 I-5Swallw / (U \j=lI5.2i-l,j;. --Swallw Figure 14 (see also Figs. 4, 5) shows the collection of some I-[/wallw, which begin with Z.T. ZHUSUBALIYEV 218 et al. 1.2 Xl 0=1.56 0.14 0.155 (a) 50’ .56 m 5 0.14 15 [ 0.16 FIGURE 16 (a) Bifurcation diagram for a 1.56 and 0.14 _</3 _< 0.155 and (b) branching pattern for a 1.56 and 0.14 _</3 _< 0.16. This section intersects that region of the domain II5swallw where two stable periodic, stable periodic and chaotic or two chaotic motions can coexist. different stable k-cycles I-Iwallw u i=1 U I-Ik.2i_l,j k 5, 6, 7, 8. j=l the parameters, as IlSwallow The properties of "k,conv -iSwallow adduced properto similar the above are k,conv ties of IIk,.. There is non-uniqueness of motions in which li.e_ between the domain l-[Swallow\I-ISwallow "k \’k,conv the bifurcation curves and Fj,5.2;_,, j1,...,2i-’; i= 1,2,... (Fig’sl 14). When the boundaries of 1-[Swallw\llSwallw "k \l-k,conv are + and intersected in the points of the curves Fj,5.2;_,, +52; 3, Let us denote the part of II2wallw, where a single stable motion exists, which is uninterrupted along BIFURCATIONS OF THE HINON MAP .+ ’j,5.2i_ ;j- 1,..., 2 i- 1., i- 1,2, one can observe hard transitions from one mode to another with hysteresis as it is typical for such transitions (Figs. 15 and 16). Figures 15 and 16 illustrate only one of possible variants of change in the character of the dynamics with variation in the parameters. The branching patterns in other sections may be more complicated in comparison with those shown in Figures 15(b) and 16(b) (see Figs. 17 and 18). 219 We realize that the content of the above analysis is qualitative rather than quantitative. As it is seen from Figure 14 the real picture of the properties of wallw as a whole is substantially more complicated than presented in this paper. Finally, the case should be considered, when the trajectory of deformation passes through oFold "-’j,5.2i-1, j- 1,..., 2 i- 1., i- 1,2,... The dependence of the solutions of xc(P) (2) on the parameters for this case is qualitatively shown in Figure 19, where 1-I X [3=-0.55ot+1.079 1.68 0.89356 FIGURE 17 Bifurcation diagram for/3= -0.55c+ 1.079 where 0.89356 _< c < 1.68. 1.5 X -0.24 0.245 [3 FIGURE 18 Bifurcation diagram for c= 1.53 and -0.24 _</3 < 0.245. Z.T. ZHUSUBALIYEV 220 and reverse period-doubling bifurcations, wallw whereas in hysteretic transitions are possible. 3. While intersecting the boundaries of Hk,j., which correspond to the parameters of hard occurrence of stable cycles, catastrophic transitions from one stable motion to another or catastrophic chaotization are possible. But such transitions are not hysteretic. 4. The sets IIk,j intersect non-emptily. Some of the regions II,j. have intersections with the domains where chaotic oscillations are realized, and that is why a great variety of bifurcation transitions is possible. IIc S/ X X Xe FIGURE 19 The qualitative plot of the variation of the stable and unstable 5-cycles with the parameters when the trajectory of deformation passes through the bifurcation point 0TM 1,5 of codimension 2. xS_ (P) and et al. xS+(P) correspond to the stable x(P) corresponds to the unstable 55cycles, and the solutions cycle. When approaching O Fld 1,5 xs_ (P), xSc+(P) and x(P) become closer and then and form the they combine in the point O Fld 1,5 single stable f-cycle, which is dependent on P uninterruptedly. The solution x.(P) is nonrough at the point O Fld 1,5 and, if we change the trajectory of deformation in such a way that it does not pass then x.(P) falls into two isolated through O Fld 1,5 solutions. 3. CONCLUSIONS 1. In the present paper we have established the domains of the modes of periodic and chaotic oscillations in the plane of parameters using numerical as well as analytical approaches. Two types of the domains of cycles stability: 1-Ik,j, 1-I/wallw, k- 1,2,... were determined. The structure of sets IIk,j, IIkswalw and their properties in whole have been studied. 2. It was shown that the motions, determined on the sets IIk,j, depend smoothly on the parameters. While moving along the parameters continuously within the limits of IIk,j, the transition from some stable cycles to other cycles occurs softly through a sequence of direct References Alligood, K. T. and Sauer, T. (1988) Rotation Numbers of Periodic Orbits in the H6non Map. Comm. Math. Phys., 12tt, 105. Anishchenko, V. (1990) Complex Oscillations in Simple Systems. Nauka, Moscow. (in Russian). Arnold, V. (1990) Catastrophic Theory. Nauka, Moscow. (in Russian). Barfred, M., Mosekilde, E. and Holstein-Rathlou, N.-H. 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